nyscience - 1. The Earth and celestial phenomena are described by relative motion and perspective

MAJOR UNDERSTANDINGS
1.1a Earth's Sun is an average-sized star. The Sun is more than a million times greater in volume than Earth.
1.1b Other stars are like the Sun but are so far away that they look like points of light. Distances between stars are vast compared to distances within our solar system.
1.1c The Sun and the planets that revolve around it are the major bodies in the solar system. Other members include comets, moons, and asteroids. Earth's orbit is nearly circular.
1.1d Gravity is the force that keeps planets in orbit around the Sun and the Moon in orbit around the Earth.
1.1e Most objects in the solar system have a regular and predictable motion. These motions explain such phenomena as a day, a year, phases of the Moon, eclipses, tides, meteor showers, and comets.
1.1f The latitude longitude coordinate system and our system of time are based on celestial observations.
1.1g Moons are seen by reflected light.
1.1h The apparent motions of the Sun, Moon, planets, and stars across the sky can be explained by Earth's rotation and revolution.
1.1i The tilt of Earth's axis of rotation and the revolution of Earth around the Sun cause seasons on Earth.
1.1j The shape of Earth, the other planets, and stars is nearly spherical.